selden



(No Model.) 7 3 Sheets-Sheet 1.

G. SELDEN.

FIRE AND POLICE ALARM TELEGRAPH. No. 321,058. Patented June 30, 1885.

Nv PETERS. Pholo-L'flhognpher, Wnhingmn, D. Q

(No Model.) 3 Sheets-Sheet 2. 0. SELDEN.

FIRE AND POLICE ALARM TELEGRAPH.

Patented June 30, 1885.

WZwesses (No Model.) 1 3 Sheets-+Sheet 3.

U. SELDEN.

FIRE AND POLICE ALARM TELEGRAPH.

Patented June 30, 1885. .ZTL'Q2J3.

lllNrTnn' STATES PATENT Garrett,

CHARLES SELDEN, OF BALTIMORE, MARYLAND.

FIRE AND POLICE ALARM TELEGRAPH.

TJPECIFICATION forming part of Letters Patent No. 321,058, dated June 30, 1885,

Application filed March 13. 1884, (No model.)

To all whom it may concern.-

Be it known that I, CHARLES SELDEN, a citizen of the United States, and a resident of Baltimore, in the State of Maryland, have invented certain new and useful Improvements in Fire and Police Alarm Telegraphs, of which the following is a specification.

My invention relates to systems of telegraphic communication in which automatic signaling-boxes, such as fire or district telegraph boxes, constructed to send a definite or predetermined signal, are combined on the same general circuit with Morse keys or other transmittingdevices worked by hand.

My invention is intended more especially for use with fire and police alarm telegraph systems, but is not limited thereto, since the signals sent by the box, hereinafter described, may be of any character and for any purpose.

The principal object of my invention is to provide means whereby signals or alarms, as, for instance, for fire or police, may be transmitted to a central station over a wire or circuit, and whereby at the same time the same wire or circuit may be used for ordinary signaling purposes in signaling from one alarm or call box to another, or to the central station, without operating the main relay at the central station by which the calls or alarms from the automatic apparatus in the boxes are received, thus admitting of the use of the wire or circuit for two purposes.

The object of my invention is also to so arrange and construct the circuits and apparatus that should the wire break or ground notification will be given at the central office, while at the same time the box or automatic signals of fire, police, or other character will be transmitted by the signal apparatus the same as if no break or ground had occurred.

My invention consists in the novel arrangements of circuits and apparatus hereinafter described and claimed, and primarily in the combination, with a loop or closed circuit grounded at the central station, of a differential relay, one leg of which is in one and the other in the other side or leg of the loop, and two sections of main battery, one in each side, combined to reinforce one an other on the loop-circuit, but by; reason of the differential winding of the relayftoproduce no effect on the l'atter'so long as the loop-circuit is closed,

or both legs or sides of the loop are grounded so as to provide circuit for both sections of battery. By this arrangement, the relay be ing normally unaffected, ordinary signals may be sent over the loop-circuit by breaks and makes of the same, and received at any point on a relay or magnet charged by the combined current of the batteries without affecting the aid relay, whose office is to receive the signals sent by the automatic district fire-alarm or other boxes.

In carrying out my invention, 1 may employ any desired form of relay, but, as will hereinafter appear, it is preferable to employ the novel form of relay hereinafter described, and consisting of a horseshoe-magnet having a bisected yoke and a bisected or divisible armature, so that it may be changed from a single relay to two separate relays, each in a separate side or leg of the grounded loop circuit.

My invention consists, also, in the combination, with the loop-circuit, of the receiving 1'64 lay at the central station, and double sets of insulating and conducting stops for the relaylever, reversed in position, and means for bringing one or the other set at pleasure into range with the lever, so that it may work either on closed or open circuit, according to the condition of the loopcircuit, as hereinafter described.

Myinvention consists,also,in acertain novel plan of automatic signal-box, the main feature of which lies in so constructingit that each element of a signal shall be represented in the circuit closing and breaking wheel or wheels of the box by means for opening theloop-circuit and means for grounding both legs or sides of the loop to either side of the box, one after the other, so that, as will be hereinafter described, each element of the signal to be sent shall be transmitted either by break of circuit, by grounding the line to one side of the box, or by grounding the line to the other side of the box.

My invention consists, also, in a compound transmitting disk or wheel, made in three portions, independently adj ust-able upon the same shaft, whereby the order of the breaking and closing of the line and ground connections 7 may be varied, as hereinafter described.

My invention consists, also, in certain other details and combinations of circuits, apparatus, and parts necessary to the carrying out of my invention in the best manner now known to me, the nature of which sub-inventions will be hereinafter more particularly described, and which inventions will be specified in the claims.

In the accompanying drawings, lhave shown some of the best mechanical construction of parts now'known to me, whereby the principles of my invention may be carried into effect; but I do not wish to be understood as limiting myself in this respect, the gist of the invention consisting, rather, in the electrical circuits and connections and the methods of sending the desired signals by the changes of circuits and the opening and closing of line and earth connections, hereinafter described, no matter by what mechanical or magnetic constructions they may be effected.

In the accompanying drawings, Figure 1 is an elevation of a portion ofa fire-alarm or district telegraph box, illustrating the novel principle of circuit closing and breaking wheel forming a part of my invention. Fig. 2 is a diagram of circuits. and connections illustrating my invention. Fig. 3 is a plan view of a relay constructed according to my invention, and illustrates more especially the novel arrangement of stops for the relay-lever. Fig. 4 illustrates in perspective the construction of the devices whereby the stops may be adjusted so that a relay-lever may work on open or closed circuit. Fig. 5 illustrates diagrammatically the local circuits and connections employed with the compound relay form inga portion of myinvention. Fig.6isarear or yoke view of the relay-magnet,aud illustrates the preferred construction of the device whereby the yoke may be divided to make of the horseshoe relay-magnet two single relay-mag nets. Fig. 7 is a plan of the same, one side of the connecting-yoke being broken away to show the construct-ion. Fig. 8 is a detail view showing in elevation the compound relay armature and lever and illustrating the means whereby the armature is bisected or divided so that each half may act as a single and independent armature for each half ofthe bisected or divided relay-magnet. Fig. 9 shows in plan a view of the armature itself, one sideof the connecting-piece being broken away. Figs. 10 and 11 show in elevation and plan the adj ustable bell-magnet employed in carrying out my invention. Fig. 12 shows in edge view a compound circuit-closing wheel with the adjusting features whereby variations in the order of grounding the two sides or legs of the loop-circuit and of opening the same may be made. Figs. 13, 14, 15, 16 indicate some of the variations that may be made by adjustment of the wheels. Figs. 17, 18, and

19 illustrate diagrammatically modified arrangements of circuits, batteries and magnets.

Referring to Fig. 1, W" W W indicate three circuit. closing and breaking disks or wheels, mounted on a suitable wheel or arbor, after the manner ofthe circuit-closing disk or wheel of an ordinary fire-alarm or district-messenger boX,so as to be operated upon the pulling of a handle,winding up ofa spring, or other operation,in the usual and well-known manner, and upon completing a revolution or revolutions to always come to rest at the same spot. The disks are preferably of metal and are electriccally connected with one another, and in practice may be of the same diameter, and, if desired, made from a single piece. They are here represented as of different diameters in order to better show the construction and relation of the circuit making and breaking portions. If the order of the makes and breaks of contact be made variable, the construction hereinafter described and shown in Fig. 12 may be adopted.

G Z Z indicate three circuit closing and breaking springs whose ends project over the disks, and are arranged so that when the apparatus is at rest the springs Z Z will rest, respectively, in contact with disks WV W, so that a circuit will be.closed between them while spring G is out of contact with its disk WV".

Disks \V W are provided, respectively, with a series of circuit-breaking notches, n n", and the disk WV is provided with a similar number of circuit-closing projections, g. The projections g, as well as the notches, are repeated on the circumference of its disk as many times as the number of signaling impulses to be transmitted, and of course vary in number and position, according to the character of the signal to be sent. In each group a n 9 about the periphery of the compound disk the same relation of the two notches and the projection g is repeated. The disk here shown is arranged to send the number 21. Spring G is the circuit-closing spring, whereby ground-conned nection is completed, while springs Z l are connected, respectively, with the two sides or portions ofthe loop-circuit to either side of the box.

The loop or complete metallic circuit is indicated by L L, and consists of a normallyclosed endless circuit, preferably of metal, containing the various signaling devices hereinafter described. Said loop circuit has a' groundconnection at the central office, as will be presently described.

When the notches and circuit-closing portion 9 are arranged in the relation shown in Fig. 1, their action is first to open the circuit between the two sides of the loop-circuit; sec- 0nd, to ground the side connected to Z; third, to also ground the side connected to I, and, fourth, to break both ground connections, leaving the two sides of the loop connected through Z Z and the disk. This series of actions is repeated a number of times and at intervals depending on the character of the signals to be sent. The order of the groundings and breakings of connection maybe infinitely varied without departing from the spirit of my invention. Any desired number of such boxes maybe placed on a loop-circuit ground- I appropriate bearings, as indicated.

ed at a central office, A, as indicated in Fig. 2, and in connection with signaling-keys K, magnetic tap-bells B M,and areceiving-relay, M R, as will be presently described more in detail. The relay M R has by preference a horseshoe-magnet, one leg of which is in the side or leg L of the loop-circuit with main battery M B, while its other leg is in circuit with the side L and main battery M B.

The batteries M B M B have their poles connected as indicated, so that the batteries will flow together over the closed loop-circuit and through the coils on both legs of the relay, so as to charge and hold up the armatures of the bell-magnets B M. The armature of the relay-magnet is, however, unaffected under this condition, because the coils on the two legs of the relay are so wound and connected in wellknown fashion that they will neutralize one anothers effects on the magnet-core, and the armature of the relay will, therefore, remain unattracted so long as both batteries have circuit either through the loop or through the ground at the central office, and a ground at a box, B. If, however, either battery act alone, the armature of the lever will be drawn up and cause the recorder in the local circuit controlled by said relay to record a signal. The relay will likewise obviously remain unaffected if both batteries cease to flow through the relaycoils, as will be the case if the loop-circuit be simply broken. It will from theseconsiderations be obvious thatthe breakings and closing of the circuit produced by the keys K, although producing signals on the bell-magnets by opening and closing the charged loopcircuit,will produce no signal on the relay.

In general I prefer to construct the relay so that either leg thereof may act as a relay-magnet independently of the other, and upon the same lever or portions of lever employed when the two legs act as one magnet. To accomplish this end I make the yoke of the magnet, as well as the armature, divisible by means of removable connecting-pieces serving to magnetically connect and disconnect the two cores or sides of the magnet, as well as the two sides of the armature presented to said cores. This construction, as well as a novel arrangement of the relay contacts or stops, whereby I am enabled to readily meet some of the conditions that may arise in the operation of the apparatus, are illustrated in Figs. 3, 4, 5, 6, 7, 8, and'9.

0 indicates the armature for the horseshoemagnet relay, which armature is mounted on and connects the two levers a a, each of the latter being mounted in the usual manner on The center of the armature consists of a removable piece of iron, 0*, fitted in grooves c c, or otherwise arranged to closely connect the two ends of the armature, or to permit said armature to be bisected.

The yoke D of the horseshoe-magnet is similarly provided with a removable piece of iron, D that, when in place, magnetically connects the two cores of the horseshoe-magnet, but when removed bisects the magnet, so that each half may act independently of the other upon one portion of the bisected armature O and the lever a or a, carrying the latter.

Each relay-lever works between front and back contact-stops of any usual or desired construction, but in the present instance I provide two sets of such contact-stops for each lever, one set indicated by the letter da'nd the other set by the letter d Stops cl are reversed in position from d", as indicated, so that, as will be obvious, if the armature-lever plays between a pair, d, circuit will be closed when the lever is drawn forward against its front stop and broken when it is drawn against its back stop, while, on the contrary, if the set d be moved into position on the two sides of the lever the operation will be reversed and the lever will close circuit on its back stop and open on its front stop. The stops may be shifted, so as to bring either set into operative relation with the lever, by mounting them on a suitable adjustable frame or block, (indicated at f*,) which is made adjustable in a suitable guideway,f*, running transverse to the line of motion of the lever, by means of a screw, f 7

' The frames or blocks for the two levers are independently adjustable, as shown, and they may be set so that both levers shall close on the front contact or both open, or one may be set so that its lever shall close on the front stop while the other is set so that its lever shall open circuit on the front stop, or vice versa.

The two blocks or frames f, and therefore the circuit-closing stops on both, are electrically connected in any usual or suitable manner with one pole of a local circuit containing a receiving or recording instrument, R, of any suitable or usual construction, while the levers a a or the frame supporting said levers, is connected with the other pole of the local circuit, as diagrammatically shown in Fig. 5, and as will be well understood by those skilled in the art. The local circuit contains any form of receivirig-instrument desired-such as a sounder, Morse register, or other indicating or recording instrument, as is well understood in the artand also the usual local battery. The local-circuit receiving-instrumeut is here typified by an ordinary electro-magnet,which may be a sounder-magnet or the controlling or actuating magnet of any other receiving-instrument.

The bells of the bell magnets B M are made adjustable on a suitable support, S, and the bell-hammers play inside of the bell, so that by adjusting the bell in the are of a circle or in a rightline to permit the hammer to strike on one or the other side, the magnet may be made to trip the bell either by the opening or closing of the circuit. A setscrew, 8*, serves to secure the arm supporting the bell in proper position to permit the hammer to strike either on being drawn forward by the magnet B M or on being retracted therefrom.

Referring again to the diagram, Fig. 2, as many boxes B, containing the signaling mechanism described, are placed on the loop-circuit, and by preference each is provided, as indicated in Fig. 1 and in the diagram, with a bell-magnet, B M, and a circuit-breaking key, K, to permit communication to be held between any box and another box or the central office. at which latter are also placed bell-magnets B M and keys K in each side or leg of the loop-circuit. Bell -magnets and keys may, if desired, be placed at other points on the loop. The two sides or legs of the loop starting from ground at the central office are indicated by the letters L L Under normal conditions the two legs of the relay-magnet are connected by their bridgepiece, and the piece 0 of the armature 0 being in position said armature acts as an ordinary armature to the relay. The stops for the levers a a are set so that on back contact said levers will rest against insulating-stops. The cireuits and position of the apparatus are now as indicated in Figs. 1 and 5, and the keys K being at rest and closed, the loop-circuit is complete through said keys and the springs Z Z and metallic disks, said springs being in each box connected, respectively, with the sides of the loopcircuit to either side of the box. The ground at each box is open, spring G. which-is connected to ground, being disconnected from the disk. Batteries M B and M B now flow through the loopcircuit and the'two relay-coils of M It, but produce no effect on said relay, because the effects of the current which flows in one leg and tends to produce poles, say, as indicated by the signs and are counteracted by the effects of the same current flowing in the other leg in such direction as to tendto produce polarity of the opposite sign in the ends of the horseshoe-magnet. bell-magnets B M,.and holds up the armature bell-hammers away from the bells.

On operating any key K, signals may be produced on any bell in the loop by the breaking and closing of the loop-eireuit for the two batteries M B M B but the armature 0 remains retracted because the effect of breaking the loop is simply to withdraw all current from the relay, and the effect is therefore practically the same as when the battery-current flows simultaneously in both legs with neutralizing effects. WVhen a box is operated, the action is as follows: The circuit-controlt ing wheel, moving by clock-work or other means, in the direction. of the arrow, the first effect is to break the loop-circuit by bringing the notches or insulating-spaces n a under the springs Z Z No effect is produced by this on the relay M R for obvious reasons. As the wheel revolves, spring Z makes contact with the circuit-closing disk, spring Z being as yet out of contact owing to the greater length of the notch or insulating-space a As spring The same current flows in the Z closes, contact spring G makes contact with circuit closing projection or space g. The side or leg L of the main-line loop is now grounded, side L being in the meantime open, and circuit is thus made for battery MB from ground at box through spring G, circuit-closiug-wheel spring Z, side L of loop-battery M B, one side of relay-magnet, and to ground at central office, thus causing thearmaturelever to be attracted and the local circuit of the register or recorder R to be closed. As the wheel continues to revolve, spring Z makes contact with the disk, and as, spring G is still in contact with the disk, side L of the loop is grounded, and battery M B no w finds circuit. Both sides being thus completed and current from both batteries being now permitted to circulate, their effects neutralize one another and the relay-armature falls back, thus completing the signal, or portion of signal, sent by the first group of circuit closing and breaking parts on the transmitting-wheel. As the wheel moves farther on, the circuit to ground is broken by projection y leaving spring G, but no effect ensues under the condition supposed,

since the only result is to compel the current of batteries M B M B to circulate through the loop instead of through the ground. As the wheel revolves, and other groups pass beneath the springs, the action is repeated at intervals and with a sufficient number of recurring impulses to complete the whole signal assigned to the particular box operated. At each break of the loop circuit or connection between Z Z pro duced in the above operation, the bell-magnets B M' on the loop-circuit will give the signal, as is obvious, the arma'tures of magnets B M in side L of the loop-circuit falling back when the springs Z Z reach the insulatingspace on the wheel, and being drawn up when the spring Z resumes contact with the disk, so

as to ground side L and make circuit again for battery M B, while the armatures of mag- IIO nets B M on side L of loop-circuit fall back when'spring Z reaches the circuit-breaking space, and are drawn up again when side U is grounded through Z wheel, and G. If at any time the loop-circuit should be broken by ac cident or design, as at a point, A, and both sides remain free from connection with ground, the signal would be received on relay M R from the box operated, just as if the linewere unbroken. In this case the breaking of the line-circuit will give a signal on the tap-bells on the loop-circuit both at the central oflice and at other points, and the bells may be then adjusted so as to be tapped at every completion of circuit to ground by the action of a box mechanism. -Under the condition supposed, the signal will be sent from a box on the side L of the loop between the break and the cen. tral office by the make and break of ground connection, produced as spring G touches and leaves projection g, circuit being made when 9 reaches G, (spring Z being at such time in contact with the disk,) and broken when the projection 9 leaves spring G. From boxes in the side L", between the break and the central office, the signaling-impulses will begin to flow when spring Z (after breaking at n") makes contact with the disk, (g being already in contact,) and will cease to flow when 9 leaves spring G. Signals coming from boxes in side L will be produced by the making and breaking of a ground-circuit for battery M B through one coil of the relay, which action alternately charges and discharges the relay,while signals from side L will be producedin asimilar way by the action of battery M B acting alone. Should the line be grounded at same point so as to make earth-connection for both sides of the loop, the effect of batteries M B M B on the bell-magnets in each side at central oflice would be lessened, since each would be affected by the current of one battery only, instead of two, and their retractors being properly adj usted for this purpose, the armaturcs would be drawn back and tap the bells, thus giving notice of ground-connection. The retractors may, if desired, be then adjusted to permit the magnets to draw up the armatures, so that signals 011 the bell will be produced by the breaking and closing of the loop-circuit between the bell magnet and the accidental ground as follows, provided the point of grounding be such that it produces no effect on the relay: It being supposed that the relay-levers a (t are against their back or nonconducting stops, and batteries M B M B each find ground at A over a side of the loop and through the springs Z Z*, the signal sent by a box in side L will be produced by the opening and breaking of the circuit thus formed for M B, because at each opening battery M B is permitted to act unopposed on the relay and draw up the armature-lever to close the circuit of the register.

A box in side L will open circuit-battery M B when its spring Z reaches notch n, and will close said grounded side and keep it grounded when spring Z again makes contact with the disk, the ground-circuit being first formed through G and g at that box, then through Z-,as thelatter agai n makes contact, and g G, and finally through Z, only as projection 9 leaves spring G. Boxes in side L" send signaling-impulses in breaking ground for the side L when spring Z reaches the notch a and completing a ground for that side when the projection g reaches the spring G.

If the ground at A were in such a position as to give the battery on one side of the loop acircuit of less resistance than that formed for the battery on the other, thus giving to the former the advantage and tendency to cause armature of the relay to be drawn up, and cause register R to run continuously, the contacts of the levers a a" are adjusted so as to bring the insulated front stops into range of the armature and the uninsulated or contact stops into position to close the local when the armatures are retracted. The magnet and the armature 0 being divided by removing the connecting pieces 0 D each half of the of the loop makes a ground for that side.

this case each side of the loop-circuit between central office and ground works on normallyclosed circuit and the local is closed and broken by the action of the battery in the same side on breaking and making of an external ground-circuit for'that side of loop instead of by the action of the battery in the other side of the loop, as in the case just supposed, where the loop is grounded and relay M R is left to act as a single relay.

If side L of line should be grounded and side L remain open or suspended free from ground-connection,- the stops for armaturelever a are adjusted to cause operation of register on falling back of lever against a circuitclosing or uninsulated stop, while stops for armature-lever c are set so that the latter'will close circuit on front contact when the transmitter in the box operated in the open side In this case each armature and relay formed by dividing the horseshoe-magnet and its armature will actin obvious manner, the one, a, by opening and closing of a ground-circuit for side L by the revolution of the disk in the sig nal-box, and the other, 06-, by the making and breaking of a ground by means of the spring G acting in conjunction with springs Z Z.

It will thus be seen that by constructing the transmitter of the signalbox to break the loopcircuit as well as to ground one side and then the other for each character or element of its signal, any box will cause its signal to be recorded regardless of the condition of the line, whethergrounded on both sides, grounded on one side and open on other, or open on both.

The cutting of the three wires connected, respectively, to springs Z, l, and G will render that one box useless; but all other boxes on the circuit can still transmit their signals. The cutting of but one wire will not prevent the box from sending its signal to the central station. I do not limit myself to locating the main batteries in the particular position shown in Fig. 2, as they may be placed in other positions in the two sides or legs of the loop-circuit, respectively-as, for instance, between the relay-magnet and the ground-connection at the central office, as indicated at M 13*. The form and construction of the circuit-closing wheel in the box whereby the loop-circuit is opened and the two legs are grounded one after the other for the purpose of sending the signal either by the opening of a grounded side of the loop or by the grounding of an open side or ofthe complete loop,may

It is not necessary that the opening and c1osing of contacts between the springs Z Z G and the disk should follow in the particular order or relation produced by arranging the circuitbreaking spaces a n and the circuit-closing space 9 in the relative positions shown in Figs. 1. and'2. They may have other orders of open circuiting and el-osing the loop-circuit and closing and opening the ground for the two sides thereof. Some of the various arrangements that may be employed are illustrated in Figs. 13, 14., 15, and 16, and by properly constructing the circuit-closing disk or wheel any one of the arrangements shown maybe the desired connections is as follows, as will be plain from an examination of the figure: Both sides L L ground-ground for side L opens, ground for side L opens, loop-circuit opens, loop-circuit closes. In Fig. l4c both sides first ground, then side L opens, side L opens, loop-circuit remains open until Z again closes contact. In Fig. 15 is shown the arrangement of Fig. 1. In Fig. 16 Z breaks contact, opencircniting loop. Then Z makes contact, but Z breaks simultaneously and G makes contact, thus grounding side L only. Z makes contact and L is grounded. G breaks contact, opening ground for L and L and leaves Z Z in contact and loop-circuit closed. 7

The above arrangements will be seen on investigation to answer the various requirements arising from the changes of condition of the loop-circuit, already set forth, and arising either from accident or design, so that any box will transmit and record its signal either by grounding one side or the other of the loopcircuit (either when the loop-circuit is complete or when it is open) or by open-circuiting such loop-circuit when one or the other side thereof is grounded.

Other arrangements of the particular opencircuiting and closing spaces n n 9 might bev made to do the work with particular conditions of the line, and other proportions or constructions of the parts might be used without departing from the invention.

The box described also admits of employment with a loop-circuit whose relay-magnets and batteries are arranged as shown in Fig. 17. In this case the main battery is in the ground branch taken from the loop at the central office, and the relays work separately on their armature-lever a a". The stops are adjusted so that a a are normally held by their retractors against insulated back stops; but

the operation of either armature, or both to gether, will close the register or recorder circuit. The box or automatic transmitter may have the arrangement of circuit closing and breaking spaces of Fig. 1, as indicated. If the loop-circuit is intact, signals will be sent from the box by the closing and opening of earthconnection through Z, Z, and G, the breakings of the loopcircuit producing obviously no effect on either relay. If the loop-circuit be grounded, the relay-contacts are set so as to open local, while armatures a a" are drawn up, and to close the local when they are retracted, the signals being in this case produced by the opening and closing of the circuit from ground at the central office to the outer ground through the side of the loop in which the box operated lies. If one side of loop be open, the other being grounded, the contacts for the relay-lever of that side are left in the position shown, and signals are sent from the box or boxes in that side by the making and breaking of a ground-connection through G.

Signals may be sent on the loop-circuit by the opening and closing of a battery whose strength is insufficient to overcome the retractors for a and (H, which are properly adjusted for such purpose, the retractors for the bell-magnets being adj usted to the tension of such battery, so that while the loop-circuit is intact the bell-magnets will hold up their armatures, while it" the loop be opened, thus breaking the circuit of such battery, the retractors will act and withdraw the armatures of the bell-magnets. M B indicate such battery, and K and BM a signaling-key and bellmagnet, respectively.

Signals might obviously be produced on the bell-magnets over the loop-circuit by introducing a battery of lower potential than is required to operate relay-levers a a, such battery and proper key for this purpose being indicated, respectively, at M B and K while B M indicate a bell-magnet therefor.

Fig. 18 shows the same relay arrangement, but with a different arrangement of battery, which latter is here placed in the loop in two sections-one in each side of loop between re lay-magnets and ground. The batteries having their poles arranged as shown re-enforce one another, and both relay-magnets are normally charged by the current flowing in the loop-circuit. The contacts for the two armature-le'vers are set so as to close local when either armature drops back. The signal is sent from the box when the loop-circuit is in normal condition by the opening of the loopcircuit, the grounding of the same under this condition producing no effect excepting to reclose the circuit of the batteries through ground after the breaking produced by springs Z Z passing the open-circuiting spaces on the wheel. If the loop-circuit be grounded, the signals are sent from the box in one side L or L" by the open-circuiting of that side, thus breaking the battery, which finds circuit from ground at central office through a relay, the side of loop containing box, and distant ground. If one side be open, the relayconfacts for that 'side are properly adjusted,.so that the signal shall be sent by the closing of a distant ground for the batterysection in that side through the circuit-closing devices of the box operated in that side.

Fig. 19 illustrates still another modification in which the batteries in the two sides of the grounded loop oppose one another, and the relay-contacts are therefore set to close local circuit on their front contacts and to break on their back contacts. The box-signals are sent while the loop is intact by the grounding of the loop, thus energizing one or both of the relay-magnets. If the loops be already accidentally or designedly grounded, thus furnishing normal active circuit for each battery M B M B from ground at central office through loop and distant ground, the relay-contacts are reversed, so that the relays being normally charged the local will be normally open, and signals will be sent by the opening of the side of loop in which the box operated lies. If one side be grounded and other remain open, the relay-contacts of relay in the open side are left in the position indicated-that is. so as to close the local on front contact; but the contacts of the other are adjusted so as to close local on back contact when the grounded side of loop is opened by the operation of a box in the grounded side of the loop. In this arrangement obviously bell-magnet'B M at central station will announce the grounding of line by tapping the bell on energization of magnet produced by the furnishing of an active circuit for asection of said battery in the same side of loop with the bell, said battery being then unopposed in its action by the section of battery in the other side.

Signals may be sent and received on the loop-circuit while intact by means of batteries and keys M B and K as in Fig. 17.

The peculiar construction of relay, consisting of the sets of conducting and non-conducting stops, reversed in position and combined with means for adjusting them in proper relation to the relay-lever, is not specifically claimed herein, as it will form the subject of another application for patent.

What I claim as my invention is 1. The combination,with a loop-circuitnormally grounded at a central office, of two sections of main battery, one in each side of the normally closed or intact loop-circuit, a relaymagnet coil in each side ofthe loop, and a signal mechanism having line and earth connections for sending a. predetermined or set signal, either by opening of the loop-circuit or by grounding thereof.

2. The combination,with a loop-circuit normally grounded at a central office, and having in each side or lega section of main battery whose circuit is completed normally over the loop-circuit, of a transmitter provided with circuit closing and breaking devices adapted to send a predetermined signal'by grounding both sides of the loop-circuit, one side before the other, and also by opening said loop-circuit, and apparatus at the central office responsive to breaks and ground, as and for the purpose described.

3. The combination,with aloop-circuitnormally charged, a normal ground therefor at a central office, and a relay-magnet coil in the loop at each side of the ground, of a box signaling apparatus for sendinga predetermined signal by completing a ground for the loopcircuit to each side of the box a predetermined number of limes, according to the signal to be transmitted, and for opening the loop-circuit a corresponding number of times at every operation ofthe box, whereby the signal may be sent to central office either by grounding the loop or by opening a side of the loop when accident-ally grounded, as and for the purpose described.

4. The combination, with a normallycharged loop-circuit grounded at a central office, and a differentially-wound receiver having its two coils connected,respectively, at opposite sides of the ground-connection, of a box-signal apparatus having means whereby at each opera ,tion thereof theloop-circuit will be opened to send the proper signal in case one side of the loop be grounded, and will also be grounded from both sides of the box to send the same signal in case the loop-circuit be broken,either upon one side or the other of said box.

5. The combination, with a normally-closed loop'circuit grounded at the central offiee, of two relay armature-levers, a coil or coils in each side of the normally-closed loop-circuit, a common local circuit controlled by said relaylevers, transmitters placed in said closed circuit, and receiving apparatus responsive to the changes of current produced on the closed circuit by the action of said transmitters.

6. The combination, with the grounded loopcircuit,of two relay-armatures, each controlled by a coil in one side of the loop, a common local circuit for said levers, and reversible stops whereby said levers may close said cirouit either on front or back stop.

7. The combination, with a loop-circuit grounded at a central office, of a differential relay, the two coils of which are respectively in the two sides of the loop-circuit, batteries in the two sides, respectively, of the loop, arranged to normally charge the loop, but to maintain the relay unaffected, and a signaling apparatus adapted to send its signal by grounding the sides of the loop one before the other, and by opening the loop-circuit.

8. The combination, substantially as de scribed,with a grounded loop-circuit normally charged, of a differentially-wound relay,whose coils are respectively connected so that the relay will be normally neutral, means for grounding a side of said loop-circuit to send closed loop, a relay apparatus having two controlling electro-magnetic coilsone in each side of the loopa boxsignal apparatus for sending signals either by opening a side of the loop or by grounding said loop, and Morse keys and suitable receivers in said normallyclosed loop-circuit. I

10. The combination, with a' loop-circuit normally closed and grounded at a central office, of a receiving relay-coil in each side of the closed loop, two armaturelevers-one for each sidea single local circuit, and means whereby each of said levers may be made to close the local on either front or back. contact at pleasure.

11. The combination, with a loopcircuit grounded at the central office, of a differential horseshoe relay-magnet having a divisible yoke and divisible armature, whereby said relay may be transformed into two relays, as and for the purpose described.

12. The combination, with the loop-circuit, of the bisected horseshoe-relay, bisected armature, two relay-levers, connected, respectively, to opposite ends of the armature, relay contact-stops for each lever, and a common local circuit containing a register or recorder.

13. The combination, with the grounded loop-circuit normally charged, of the differential horseshoe-magnet normally neutral, means for bisecting said magnet and its armature, relay-contacts controlled by each half of the armature, and adjustable to work on open or closed circuit, a common local circuit containinga register or recorder, and a transmitter on the loop-circuit adapted to send a predetermined signal by successively but in any desired order grounding the sides of the loop one before the other, and opening the loop for each element of the signal to be transmitted, as and for the purpose described.

either grounded side.

14:. The combination, in ajdistrict or fire telegraph system, of a loop-circuit grounded at the central office, and a diiferential relay, one coil of which is in one side and the other in the other side of the loop, and a section of battery in each side of the loop combined to normally charge the loop-circuit, without, however, charging the relay, as and for the purpose set forth.

15. The combination, with the loop-circuit, of the three transmitting disks or surfaces and the circuit opening and closing spaces thereon for each element of the signals, arranged in the manner described, to ground one side of the loop-circuit, to ground the other side thereof and to open'circuit the loop, said groundings and openings of the loop taking place in any desired order, whereby a signal will be sent according to the condition of the loop, either by grounding one side only of the loop, the other being at such time open, when the loop-circuit is in normal condition, by grounding either open side of the loop or by opening 16. The combination, in a district or fire alarm telegraph-box, of a compound signaling disk or surface consisting of three signaling disks, surfaces, or portions, independently adjustable with relation to one another, as and for the purpose described, whereby the order of the breaking of the line and grounding of the two sides thereof may be varied.

17. The combination, with the loop-circuit, of two loop-circuit disks, WV W", and a groundcircuit disk, adjustable with relation to one another about their axis, whereby the order of the breaking of the line and grounding of the two sides thereof may be varied.

18. The combination, with the loop-circuit grounded at the central otfice, of a relay-lever, a relay-coil in each side of the loop, and adjustable contact-stops,whereby each lever may be arranged to work either on open or closed circuit.

Signed at New York, in the county of New York and State of New York this 7th day of March, A. D. 1884.

CHARLES SELDEN.

Vitnesses:

THos. TOOMEY, Gno. G. OoFFIN. 

